Tower Controller described a near conflict event when issuing conflicting runway occupancy clearances; the reporter listing fatigue resulting from a quick turn from the day to mid shift as a causal factor.

Narrative

After beginning a mid shift; and less than 30 minutes after assuming responsibility for all East Tower Local and Ground positions combined; I cleared a CRJ7 to land on Runway 17C. Almost simultaneously; I taxied a MD82 to Runway 17R; an action which would require a release from the West Tower due to his SID. Another CRJ had landed prior to the CRJ7 and I had routed the other CRJ via Taxiway's M and EM with instructions to hold short Runway 17R before I eventually crossed him and taxied him to the ramp. The CRJ7 touched down on Runway 17C; exited at M3 high-speed and I instructed him to cross Runway 17R at K8; then turn left on Lima and remain on Local East-1 frequency. Immediately afterwards; the MD82 reached Runway 17R and I obtained a departure release from the West Tower. I cleared the MD82 for take off with instructions to proceed to the first RNAV fix on his SID. I observed the CRJ7 turning westbound on K8 and remembered that I had given him permission to cross Runway 17R. I immediately queried the MD82 as to whether or not they had crossed the hold-short line and when they responded in the affirmative I immediately canceled their take off clearance with instructions to 'taxi onto the runway' only. I then queried the CRJ7 as to whether he was still short of the Runway 17R hold-short line and when he answered in the affirmative; I instructed him to 'hold short of Runway 17R' which he acknowledged. I then re-cleared the MD82 for takeoff and when airborne; I instructed the CRJ7 to cross Runway 17R and to remain on Tower frequency. Honestly; this incident occurred largely due to fatigue from lack of sleep between my day shift and mid shift. For whatever reason; it was the previous CRJ's 'hold short' instruction and routing which my mind transposed over that which I had given to the CRJ7! In the future; I will utilize alertness aids such as caffeinated drinks or more rest between shifts to reduce the possibility of significant errors in judgment. While upset and shaken upon realizing this mistake; I do believe that my actions were timely in recognizing and correcting my mistake and prevented a loss of separation or runway incursion. As a rule; I don't believe that I fully grasped how physically and intellectually fatigued I was following my day shift. This incident; frankly; was terrifying to me and maximum alertness ensued immediately thereafter!